Is there a way to have a selection pause when it reaches its end? And then have it start up again by pressing ENTER? I then want it to pause again after the second selection. THANKS

In a word, no.

There may be a way to do this with mod-script-pipe (see Scripting - Audacity Manual) or by writing a Nyquist program. (see Missing features - Audacity Support)

I’m not sure what you are wanting to do, but you can pause by pressing “P”.

Make a selection and press the spacebar to play. Playback will stop at the end of the selection and the cursor will return to the beginning of the selection. Press the spacebar to play the selection again.
– Bill